1. Field of the invention
This invention relates generally to multiple speed epicyclic or planetary transmissions housed within the hub of the rear wheel of chain driven tandem bicycles with the pedal drive shaft for the rear rider on the axis of the rear wheel, coupled with a modification of a conventional bicycle frame which permits the chain to be fully enclosed.
2. Description of the Prior Art
Multiple speed bicycles commonly use either a chain and derailleur system or a chain driven rear hub employing one or more epicyclic gear trains. Tandem bicycles commonly use the chain and derailleur system with two bottom brackets and a long wheel base which increases maneuvering difficulty, particularly for offroad riding. On all chain driven bicycles the chain must be kept reasonably clean and well oiled for efficient operation and to prevent premature chain failure and chain maintenance becomes particularly troublesome if the bicycle is ridden extensively on dirt roads and trails. With the current popularity of offroad riding for recreation, a sealed chain drive which essentially eliminates chain maintenance is needed for a multiple speed tandem bicycle with a short wheel base, which can serve for single rider commuting as well as offroad recreational riding for couples. The object of the present invention is to satisfy that need.